Abstract:

There is no relevant segment design standard for special shield tunnel due to its special crosssection. As a result, the bending moment transferring coefficients of every radial joint of special shield tunnel segment are studied based on the prototype loading tests. The results show that: 1) The overall stiffness of the special shield tunnel segment structure increases with the buried depth increase; while the bending moment transferring capacities of the joints partially increase and partially decrease due to the structural stiffness ratios between the joints and adjacent segmental structure differ with each other. 2) With the increase of the lateral pressure coefficients, the bending moment transferring capacity of all joints became weaker as the structural stiffness ratio between the joint (not including the joint located in the right arch waist) and adjacent segmental structure decrease under the same buried depth. 3) The sensitivity of the bending moment transferring capacity of each joint to the lateral pressure coefficient decreases gradually while the buried depth increase. 4) The obvious bending moment transferring phenomenon is verified by analyzing the distribution of cracks on both inner and outer surfaces of the segments after ultimate failure.

Key words: special shape, shield tunnel, large crosssection tunnel, prototype test, bending moment transferring coefficient, crack